DESCRIPTION: Both Hypericum (St. John's Wort) and Echinacea extracts are extremely popular health-remedies. However, the genetic diversity and natural abundance of the putative bioactive chemicals have never been systematically addressed. Furthermore, the levels of potentially bioactive constituents are different in different commercially available preparations. In the course of this project, we will test the following hypotheses: 1) Echinacea and Hypericum species contain wide natural variation in levels of bioactive compounds, and 2) The natural abundance of the Echinacea bioactive chemical(s) is broadly affected by environmental and developmental cues. This proposal will identify accessions, stages of development, and environmental conditions that affect accumulation of bioactive compounds that affect human health. The project will determine the levels and patterns of genetic diversity in Echinacea and Hypericum, and how this influences accumulation of bioactive constituents. The project will also define the relationship between accumulation of bioactive constituents and developmental and environmental cues. The effect of exposure to abiotic stress on accumulation of bioactive compounds will be determined. This project plays a critical rold in our Dietary Botanicals Center in identifying natural genetic developmental, and environmental variation on levels and patterns of key bioactive constituents, and in determining strategies for optimizing the accumulation of beneficial compounds and minimizing toxicity. An additional critical result of the project will be a genetic "fingerprint" technology to facilitate identification of plant material of unknown provenance.